Wood-chip cutting machine

ABSTRACT

A wood-chip cutting machine includes a tool carrier which preferably has opposed concentric annular guide surfaces that extend parallel to the rotational axis and which are radially spaced from each other and which are successively offset from each other in an axial direction, a series of concentric frustoconical abutment surfaces that are axially offset from one another which fill the spaces between the guide surfaces, and a series of cutter tools that are secured to the abutment surfaces with their cutting edges parallel to the adjacent abutment surface, the cutting tools being mutually staggered so that successive cutter tools are disposed on a combined helicoidal and spiral line.

[4 1 Mar. 25, 1975 1 WOOD-CHIP CUTTING MACHINE [76] Inventor: Phi lipNilsson, Kaptensgaton B a,

82600 Soderhamn, Sweden [22] Filed: Sept. 21, 1973 [21] Appl. No.:399,721

[30] Foreign Application Priority Data Sept. 21, 1972 Sweden 12174/72[52] U.S. C1 144/176, 144/162 R, 241/92 [51] Int. Cl. B276 H08 [58]Field of Search 241/92, 278, 293, 296;

144/162 R, 176, I72, 174, 118, 312, 220, 218, 321, 326 R, 326 A, 326 B,326 C, 326 D [5 6] References Cited UNITED STATES PATENTS 3,250,3055/1966 Dunbar 144/326 B 3,304,970 2/1967 Altosaar l 144/162 R 3,308,8623/1967 Traben l 144/162 R X 3,330,315 7/1967 Tomlinson 144/162 R X3,454,063 7/1969 Mitten 144/326 R 3,461,931 Wexell 144/162 R 3,645,3082/1972 Nilsson 144/176 3,692,074 9/1972 Nilsson 144/176X 3,746,0627/1973 Nystrom et a1. 144/176 Primary Examiner-Andrew R. JuhaszAssistant Examiner-JV. D. Bray Attorney, Agent, or Firm-Hill, Gross,Simpson, Van Santen, Steadman, Chiara & Simpson [57] ABSTRACT Awood-chip cutting machine includes a tool carrier which preferably hasopposed concentric annular guide surfaces that extend parallel to therotational axis and which are radially spaced from each other and whichare successively offset from each other in an axial direction, a seriesof concentric frustoconical abutment surfaces that are axially offsetfrom one another which fill the spaces between the guide surfaces, and aseries of cutter tools that are secured to the abutment surfaces withtheir cutting edges parallel to the adjacent abutment surface, thecutting tools being mutually staggered so that successive cutter toolsare disposed on a combined helicoidal and spiral line.

6 Claims, 4 Drawing Figures 1 WOOD-CHIP CUTTING MACHINE BACKGROUND OFTHE INVENTION This invention relates to a machine by which a wooden logis cut up into wooden chips.

Wood-chip cutting machines are of known types. One type has thedisadvantage that under certain weather conditions, the machine may givean undesired high proportion of chips of too small size.

Another machine has the disadvantage that each knife at every passagethrough a log cuts a slice at an angle to the grain direction and suchslice has a comparatively large surface. Therefore, the log is subjectedto heavy stresses and consequently, it may start to vibrate. Where sucha cutter is designed to function as a plan-reducer, such vibrationsresult in a poor surface quality on the resulting block. (A plan-reduceris one wherein excess material is cut away from the sides of the log sothat the log is made flat on one or on opposite sides.) Where suchmachine is used as a pure chip cutting machine, such vibrations causethe chips to have an unequal quality. Also, the final end of the log maytend to turn in such a way that the knives of one of the disks cutsnearly perpendicular to the grain direction whereas the knives of theother disk cut nearly in a plane containing the grain direction, inwhich case slices of very great fiber length are obtained.

Accordingly, it is a principal object of the present invention toprovide a chip cutting machine wherein the just-mentioned drawbacks areavoided.

According to the present invention, a tool carrier is provided that hasconcentric annular guide surfaces perpendicular to the rotational axisand which are radially spaced from each other and each successivelyoffset in an axial direction, a series of concentric frustoconicalabutment surfaces that are also axially offset from each other and whichfill the spaces between the guide surfaces, and a series of cutter toolssecured to such abutment surfaces and projecting therefrom with theircutting edges parallel to the adjacent abutment surface. The cuttertools are mutually staggered so that successive cutter tools aredisposed on at least one combined helicoidal and spiral line which,where more than one such line is provided, go into each other and aremutually concentric, so that when logs are fed lengthwise toward thecarrier in a plane perpendicular to the rotational axis, the cuttingedges cut essentially in a plane at an angle to the grain direction ofthe log.

Many other advantages, features and additional objects of the presentinvention will become manifest to those versed in the art upon makingreference to the detailed description of the accompanying drawings inwhich a preferred structural embodiment incorporating the principles ofthe present invention is shown by way of illustrative example.

ON THE DRAWINGS 1 modified form of chip cutting machine.

AS SHOWN ON THE DRAWINGS A wood-chip cutting machine provided inaccordance with the principles of this invention is shown in FIG. 1,generally indicated by the numeral 10. The machine includes a pair offrusto-conical tool carriers or cutter disks 11, 12 carried on a shaft13 which is horizontally rotatably supported in a pair of bearings 14,15. The shaft 13 is driven by means ofa pulley or other transmission 16,the tool carriers 11, 12 being corotatable with the shaft 13. Thefrusto-conical tool carriers 11, 12 have their smaller ends facing eachother and in this embodiment are secured together in abutting relation.The machine 10 is equipped with suitable guide 'means such as a conicalguide roll 17 and a support member 18. The guide means 17, 18 enable alog to be fed longitudinally toward the conical surfaces of the toolcarriers 11, 12 perpendicularly to the shaft 13.

As shown in FIG. 2, each of the tool carriers ll, 12 is stepped, that iseach surface is composed of a number of concentric annular guidesurfaces 19-23 which lie in planes perpendicular to the rotational axisof the shaft 12, and these guide surfaces 19-23 are separated from eachand connected to each other by a series of concentric frusto-conicalabutment surfaces 24-28. The guide surfaces 19-23 are thus radiallyspaced from each other and are successively offset in an axialdirection, while the abutment surfaces 24-28 are likewise axially offsetfrom each other to fill the spaces between the guide surfaces 19-23. Thegeneratrix ofeach of the abutment surfaces 24-28'forms an angle with therotational axis, and the radial length of such generatrix is one to fourtimes the radial length of the adjacent annular guide surface 19-23, apreferred ratio being that the generatrix is twice as long as theadjacent annular guide surface. All of the surface'portions 19-28 areconcentric with the rotational axis of the shaft 12.

A series of cutter tools 29-33 is so disposed that individual cuttertools are secured to the abutment surfaces 24-28 respectively, andproject therefrom. The edges of each cutter tool 29-33 are disposed tolie in a plane parallel to the respective frusto-conical abutmentsurface 24-28 as is indicated in chain lines in FIG. 2.

As seen in FIG. 3 the successive cutter tools 29-32 are arranged in anangularly staggered manner in a spiral pattern. Beginning with thecutter tool 29, disposed on the surface 28, the next cutter tool 30 isdisposed on the surface 27 with a certain angular lag as seen in thedirection of rotation, indicated by the arrow, and that the nextfollowing cutter tool 31 follows with a corresponding angular lag. Inthe example shown on the drawings, each of the tool carriers 11, 12 hasits cutter tools disposed in four such spiral patterns. As the surfaces24-28 are axially offset, and as the surfaces 24-28 are concentric witheach other, the resulting line on which the cutter tools 29-33 isdisposed is a combined helicoidal and spiral line. Where a plurality ofsuch lines is provided, they go into each other and are mutuallyconcentric.

The radial extent of the guide surfaces 19-23, the rotary speed of thetool carriers 11, 12 and the angular lag between the successive cuttertools 29-33 are chosen in such a manner that each cutter tool will cut astrip with as full a cross-section as possible, similar to the crosssection of the portion denoted 34 in FIG. 2. While only two cutter teeth30, 35 are shown for each tool carrier in FIG. 2, there is alsoillustrated in chain lines the space through which the other cutterteeth pass during rotation.

Chip cutting takes place on the ends of the log, with the log resting onthe guide means 18 which may be referred to as'an anvil plate and whichprotrudes in between the conical tool carriers or cutter disks ll, 12.The edge portions of the guide 18 is preferably stepped so that theedges of the guide 18 are disposed very close to the planes in which thecutting edges of the cutter tools are moving. As seen in FIG. 3, thisanvil plate or guide means 18 is disposed slightly below the rotationalaxis. As the cutter tools 29-33 pass through a log. the cutting toolshave a feeding action on the log so that the log is pulled into themachine, preferably into a more or less complete abutting relationshipto the frustoconical surface portions 2428.

In this operation, each cutter tool 2933 has to work on only astrip-shaped portion of the log so that an even and smooth operation ofthe machine is obtained. The fiber length in the severed portion cannever exceed the length of the individual cutting edges even if the endportion of a log should take an inclined position relative tothe'central plane between the tool carriers 11, 12 perpendicular to theaxis of rotation of the shaft 12.

FIG. 4 illustrates a similar wood-chip cutting machine which has beenprovided with two additional features. in this embodiment, the machineis constructed as a so-called plan-reducer wherein the tool carriers11a, 12a are disposed at a small distance from each other which ispreferably adjustable. As a log is fed into the machine between thecarriers 11a, 12a, the logs are made plane on two opposite sides. Inorder to further improve the quality of the surface finish, the toolcarriers 11a, 12a are provided with center disks 36, 37 each havingcutter tools sized to cut considerably finer chips. The details of thecenter disks 36, 37 are known from the prior art and need not thereforebe described further.

I claim:

l. A wood-chip cutting machine comprising:

a. at least one tool carrier adapted to be driven about a rotationalaxis, said carrier having a series of concentric separate annular guidesurfaces extending perpendicularly to the rotational axis and radiallyspaced from one another, said annular guide surfaces being successivelyoffset in an axial direction. said carrier having a series of concentricseparate frustoconical abutment surfaces axially offset from one anotherand respectively filling the spaces between said annular guide surfaces,the generatrix of each of which forms an angle with the rotational axis;and

b. a series of cutter tools respectively secured to and projecting fromsaid frustoconical abutment surfaces, each tool having a main cuttingedge parallel to the adjacent frustoconical abutment surface, saidcutter tools being so mutually staggered that the successive cuttertools are disposed on a combined helicoidal and spiral line, wherebywhen logs are fed lengthwise toward said carrier in a planeperpendicular to the rotational axis, said cutting edges cut essentiallyin a plane at an angle to the grain direction of the log.

2. A chip cutting machine as claimed in claim 1 in which said cuttertools are disposed in a plurality of combined helicoidal and spirallines which go into each other and are mutually concentric.

3. A chip cutting machine as claimed in claim 1 in which the length ofsaid generatrix is between one and four times the radial length of theadjacent annular guide surface.

4. A chip cutting machine as claimed in claim 3, the length of saidgeneratrix is substantially twice said radial length. 1

5. A chip cutting machine as claimed in claim 2 in which the length ofsaid generatrix is between one and four times the radial length of theadjacent annular guide surface.

6. A chip cutting machine as claimed in claim 5, the length of saidgeneratrix is substantially twice said radial length.

1. A wood-chip cutting machine comprising: a. at least one tool carrieradapted to be driven about a rotational axis, said carrier having aseries of concentric separate annular guide surfaces extendingperpendicularly to the rotational axis and radially spaced from oneanother, said annular guide surfaces being successively offset in anaxial direction, said carrier having a series of concentric separatefrustoconical abutment surfaces axially offset from one another andrespectively filling the spaces between said annular guide surfaces, thegeneratrix of each of which forms an angle with the rotational axis; andb. a series of cutter tools respectively secured to and projecting fromsaid frustoconical abutment surfaces, each tool having a main cuttingedge parallel to the adjacent frustoconical abutment surface, saidcutter tools being so mutually staggered that the successive cuttertools are disposed on a combined helicoidal and spiral line, wherebywhen logs are fed lengthwise toward said carrier in a planeperpendicular to the rotational axis, said cutting edges cut essentiallyin a plane at an angle to the grain direction of the log.
 2. A chipcutting machine as claimed in claim 1 in which said cutter tools aredisposed in a plurality of combined helicoidal and spiral lines which gointo each other and are mutually concentric.
 3. A chip cutting machineas claimed in claim 1 in which the length of said generatrix is betweenone and four times the radial length of the adjacent annular guidesurface.
 4. A chip cutting machine as claimed in claim 3, the length ofsaid generatrix is substantially twice said radial length.
 5. A chipcutting machine as claimed in claim 2 in which the length of saidgeneratrix is between one and four times the radial length of theadjacent annular guide surface.
 6. A chip cutting machine as claimed inclaim 5, the length of said generatrix is substantially twice saidradial length.